CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES

**Definition:** This place covers:

**Glossary:** - Air: a mixture of gases containing free oxygen and able to promote or support combustion - Primary air: air supplied to the burning fuel in order to liberate combustible gases - Secondary air: air supplied to the combustible gases liberated by the primary air in order to complete their combustion. The term "secondary air" covers "tertiary air" etc. - Ash: means any solid combustion residues, for example remaining in the fuel bed or suspended in the flue gases - Burner: a device by which fluid fuel or solid fuel suspended in air is passed to a combustion space where it burns to produce a self-supporting flame - Combustion: means the direct combination of oxygen gas, e.g. in air, and a burnable substance - Combustion chamber: a chamber in which fuel is burned to establish a self-supporting fire or flame and which surrounds that fire or flame - Combustion zone: the part of the apparatus where the reaction takes place between air and fuel - Firebridge: a low wall separating the fuel bed from adjacent flue gas passages in apparatus for combustion of solid fuel, for example in reverberatory furnaces or fire-tube boilers - Flue gases: any gaseous products of combustion - Grate: a perforated surface, e.g. a grid, which supports or delimits a bed of burning fuel and serves to supply primary air